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Reworked o/f/m/gc/i/t flags

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This is mainly to free up space for flags, we're pretty close to running
out of 32-bits with future planned features:

1. Reduced file type info from 8 -> 4 bits

   We don't really need more than this, but it does mean type info is
   no longer a simple byte load.

2. Moved most internal file-state flags into the next 4 bits

   These are mostly file-type specific (except LFS_o_ZOMBIE), so we
   don't need to worry too much about overlap.

3. Compacted ck-flags into 5 bits:

     LFS_M_CKPROGS       0x00000800
     LFS_M_CKFETCHES     0x00001000
     LFS_M_CKPARITY      0x00002000
     LFS_M_CKMETAREDUND* 0x00004000
     LFS_M_CKDATACKSUMS  0x00008000

     *Planned

   Now that ck-flags are a bit more mature, it's pretty clear we'll
   probably never have CKMETACKSUMS (ckcksums + small tag reads is
   crazy expensive) or CKDATAREDUND (non-trivial parity fanout makes
   this crazy expensives. So reserving bits for these just wastes bits.

This also moves things around so ck-flags no longer overlap with open
flags.

It's a tight fit, and I still think file-specific ck-flags are out-of-
scope, but this at least decreases flag ambiguity.

New jenga:

              8     8     8     8
            .----++----++----++----.
            .-..-..-.-------.------.
  o_flags:  |t||f||t|       |  o   |
            |-||-||-|-------:--.---'
            |-||-||-'--.----.------.
  t_flags:  |t||f|| t  |    | tstt |
            '-''-'|----|----'------'
            .----.|----|.--.:--:.--.
  m_flags:  | f  || t  ||c ||o ||m |
            |----||-.--'|--|'--''--'
            |----||-|---|--|.------.
  f_flags:  | f  ||t|   |c ||  f   |
            '----''-'---'--''------'

Fortunately no major code costs:

           code          stack          ctx
  before: 37792           2608          620
  after:  37788 (-0.0%)   2608 (+0.0%)  620 (+0.0%)
This commit is contained in:
Christopher Haster
2025-01-09 16:36:59 -06:00
parent 726bf86d21
commit 5f6dbdcb14
3 changed files with 119 additions and 139 deletions
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lfs.h
+47 -46
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@@ -137,15 +137,15 @@ enum lfs_type {
#define LFS_O_FLUSH 0x00000040 // Flush data on every write
#define LFS_O_SYNC 0x00000080 // Sync metadata on every write
#define LFS_O_DESYNC 0x00000100 // Do not sync or recieve file updates
#define LFS_O_CKMETA 0x00010000 // Check metadata checksums
#define LFS_O_CKDATA 0x00020000 // Check metadata + data checksums
#define LFS_O_CKMETA 0x00100000 // Check metadata checksums
#define LFS_O_CKDATA 0x00200000 // Check metadata + data checksums
// internally used flags, don't use these
#define LFS_o_TYPE 0xff000000 // The file's type
#define LFS_o_UNFLUSH 0x00100000 // File's data does not match disk
#define LFS_o_UNSYNC 0x00200000 // File's metadata does not match disk
#define LFS_o_UNCREAT 0x00400000 // File does not exist yet
#define LFS_o_ZOMBIE 0x00800000 // File has been removed
#define LFS_o_TYPE 0xf0000000 // The file's type
#define LFS_o_UNFLUSH 0x01000000 // File's data does not match disk
#define LFS_o_UNSYNC 0x02000000 // File's metadata does not match disk
#define LFS_o_UNCREAT 0x04000000 // File does not exist yet
#define LFS_o_ZOMBIE 0x08000000 // File has been removed
// File seek flags
#define LFS_SEEK_SET 0 // Seek relative to an absolute position
@@ -163,21 +163,21 @@ enum lfs_type {
#define LFS_F_MODE 1 // Format's access mode
#define LFS_F_RDWR 0 // Format the filesystem as read and write
#ifdef LFS_CKPROGS
#define LFS_F_CKPROGS 0x00100000 // Check progs by reading back progged data
#define LFS_F_CKPROGS 0x00000800 // Check progs by reading back progged data
#endif
#ifdef LFS_CKFETCHES
#define LFS_F_CKFETCHES 0x00200000 // Check block checksums before first use
#define LFS_F_CKFETCHES 0x00001000 // Check block checksums before first use
#endif
#ifdef LFS_CKPARITY
#define LFS_F_CKPARITY 0x00400000 // Check metadata tag parity bits
#define LFS_F_CKPARITY 0x00002000 // Check metadata tag parity bits
#endif
#ifdef LFS_CKDATACKSUMS
#define LFS_F_CKDATACKSUMS \
0x08000000 // Check data checksums on reads
0x00008000 // Check data checksums on reads
#endif
#define LFS_F_CKMETA 0x00010000 // Check metadata checksums
#define LFS_F_CKDATA 0x00020000 // Check metadata + data checksums
#define LFS_F_CKMETA 0x00100000 // Check metadata checksums
#define LFS_F_CKDATA 0x00200000 // Check metadata + data checksums
// Filesystem mount flags
#define LFS_M_MODE 1 // Mount's access mode
@@ -186,53 +186,53 @@ enum lfs_type {
#define LFS_M_FLUSH 0x00000040 // Open all files with LFS_O_FLUSH
#define LFS_M_SYNC 0x00000080 // Open all files with LFS_O_SYNC
#ifdef LFS_CKPROGS
#define LFS_M_CKPROGS 0x00100000 // Check progs by reading back progged data
#define LFS_M_CKPROGS 0x00000800 // Check progs by reading back progged data
#endif
#ifdef LFS_CKFETCHES
#define LFS_M_CKFETCHES 0x00200000 // Check block checksums before first use
#define LFS_M_CKFETCHES 0x00001000 // Check block checksums before first use
#endif
#ifdef LFS_CKPARITY
#define LFS_M_CKPARITY 0x00400000 // Check metadata tag parity bits
#define LFS_M_CKPARITY 0x00002000 // Check metadata tag parity bits
#endif
#ifdef LFS_CKDATACKSUMS
#define LFS_M_CKDATACKSUMS \
0x08000000 // Check data checksums on reads
0x00008000 // Check data checksums on reads
#endif
#define LFS_M_MKCONSISTENT \
0x00001000 // Make the filesystem consistent
#define LFS_M_LOOKAHEAD 0x00002000 // Populate lookahead buffer
#define LFS_M_COMPACT 0x00008000 // Compact metadata logs
#define LFS_M_CKMETA 0x00010000 // Check metadata checksums
#define LFS_M_CKDATA 0x00020000 // Check metadata + data checksums
0x00010000 // Make the filesystem consistent
#define LFS_M_LOOKAHEAD 0x00020000 // Populate lookahead buffer
#define LFS_M_COMPACT 0x00080000 // Compact metadata logs
#define LFS_M_CKMETA 0x00100000 // Check metadata checksums
#define LFS_M_CKDATA 0x00200000 // Check metadata + data checksums
// Filesystem info flags
#define LFS_I_RDONLY 0x00000001 // Mounted read only
#define LFS_I_FLUSH 0x00000040 // Mounted with LFS_M_FLUSH
#define LFS_I_SYNC 0x00000080 // Mounted with LFS_M_SYNC
#ifdef LFS_CKPROGS
#define LFS_I_CKPROGS 0x00100000 // Mounted with LFS_M_CKPROGS
#define LFS_I_CKPROGS 0x00000800 // Mounted with LFS_M_CKPROGS
#endif
#ifdef LFS_CKFETCHES
#define LFS_I_CKFETCHES 0x00200000 // Mounted with LFS_M_CKFETCHES
#define LFS_I_CKFETCHES 0x00001000 // Mounted with LFS_M_CKFETCHES
#endif
#ifdef LFS_CKPARITY
#define LFS_I_CKPARITY 0x00400000 // Mounted with LFS_M_CKPARITY
#define LFS_I_CKPARITY 0x00002000 // Mounted with LFS_M_CKPARITY
#endif
#ifdef LFS_CKDATACKSUMS
#define LFS_I_CKDATACKSUMS \
0x08000000 // Mounted with LFS_M_CKDATACKSUMS
0x00008000 // Mounted with LFS_M_CKDATACKSUMS
#endif
#define LFS_I_MKCONSISTENT \
0x00001000 // Filesystem needs mkconsistent to write
#define LFS_I_LOOKAHEAD 0x00002000 // Lookahead buffer is not full
#define LFS_I_COMPACT 0x00008000 // Filesystem may have uncompacted metadata
#define LFS_I_CKMETA 0x00010000 // Metadata checksums not checked recently
#define LFS_I_CKDATA 0x00020000 // Data checksums not checked recently
0x00010000 // Filesystem needs mkconsistent to write
#define LFS_I_LOOKAHEAD 0x00020000 // Lookahead buffer is not full
#define LFS_I_COMPACT 0x00080000 // Filesystem may have uncompacted metadata
#define LFS_I_CKMETA 0x00100000 // Metadata checksums not checked recently
#define LFS_I_CKDATA 0x00200000 // Data checksums not checked recently
// internally used flags, don't use these
#define LFS_i_UNTIDY 0x00001000 // Filesystem may have orphaned stickynotes
#define LFS_i_UNTIDY 0x00010000 // Filesystem may have orphaned stickynotes
// Block types
@@ -243,28 +243,29 @@ enum lfs_btype {
};
// Traversal flags
#define LFS_T_MTREEONLY 0x00000800 // Only traverse the mtree
#define LFS_T_MTREEONLY 0x00000010 // Only traverse the mtree
#define LFS_T_MKCONSISTENT \
0x00001000 // Make the filesystem consistent
#define LFS_T_LOOKAHEAD 0x00002000 // Populate lookahead buffer
#define LFS_T_COMPACT 0x00008000 // Compact metadata logs
#define LFS_T_CKMETA 0x00010000 // Check metadata checksums
#define LFS_T_CKDATA 0x00020000 // Check metadata + data checksums
0x00010000 // Make the filesystem consistent
#define LFS_T_LOOKAHEAD 0x00020000 // Populate lookahead buffer
#define LFS_T_COMPACT 0x00080000 // Compact metadata logs
#define LFS_T_CKMETA 0x00100000 // Check metadata checksums
#define LFS_T_CKDATA 0x00200000 // Check metadata + data checksums
// internally used flags, don't use these
#define LFS_t_TSTATE 0x0000000f // The traversal's current tstate
#define LFS_t_BTYPE 0x000000f0 // The traversal's current btype
#define LFS_t_DIRTY 0x00000100 // Filesystem modified during traversal
#define LFS_t_MUTATED 0x00000200 // Filesystem modified by traversal
#define LFS_t_BTYPE 0x00000f00 // The traversal's current btype
#define LFS_t_DIRTY 0x01000000 // Filesystem modified during traversal
#define LFS_t_MUTATED 0x02000000 // Filesystem modified by traversal
#define LFS_t_ZOMBIE 0x08000000 // File has been removed
// GC flags
#define LFS_GC_MKCONSISTENT \
0x00001000 // Make the filesystem consistent
0x00010000 // Make the filesystem consistent
#define LFS_GC_LOOKAHEAD \
0x00002000 // Populate lookahead buffer
#define LFS_GC_COMPACT 0x00008000 // Compact metadata logs
#define LFS_GC_CKMETA 0x00010000 // Check metadata checksums
#define LFS_GC_CKDATA 0x00020000 // Check metadata + data checksums
0x00020000 // Populate lookahead buffer
#define LFS_GC_COMPACT 0x00080000 // Compact metadata logs
#define LFS_GC_CKMETA 0x00100000 // Check metadata checksums
#define LFS_GC_CKDATA 0x00200000 // Check metadata + data checksums
// Configuration provided during initialization of the littlefs